The prime minister wants to see fewer people extradited to the United States and more prosecutions in Britain.

That is what he told President Obama when they met on Wednesday.

Both men are aware of the controversy and the diplomatic problems generated by the decisions to extradite to the US the alleged hacker Gary McKinnon, Christopher Tappin - who faces charges of breaching the Iranian arms embargo - and Richard O'Dwyer who is accused of giving access to pirated videos.

David Cameron can't launch a review of the extradition treaty since one's already been carried out and it found the treaty to have the right checks and balances.

What's more a higher percentage of British applications to extradite Americans were granted than the other way round.

So officials from the Home Office and US Department of Justice will look instead at how the treaty is working.

Will that make any difference?

Hard to say, but I know there is very little sympathy among Whitehall officials over the plight of Messrs McKinnon, Tappin and O'Dwyer.